I have a external USB drive connected to my MBWE and every night I make a backup of some directories from my MBWE to that drive. I'm using a solution where I use hard links under Linux. My script you can find here: mysnapshot

Now I have to make a copy of my backup directory and I want to preserve all of the hard links. Note: the target files for all hard links are within that directory.
I don't know how to make that exact copy of the directory. I have tried some commands, but I always get the files and not the hard links. Please give me an hint.